The present invention relates to the field of motor position sensing using Hall-effect sensors.
It is common to utilize Hall-effect sensors to detector the rotational position of a motor such as a brushless DC motor. In one common configuration, three or more Hall-effect sensors are mounted to the stator of the motor within the magnetic field of the rotor magnet which rotates during motor operation. The Hall-effect sensors generate binary outputs that provide rotational position information to control circuitry that controls the speed and/or position of the motor, including “commutation” or the sequencing of the currents provided to different windings of the motor.
In such configurations, it is known to employ individual wires to carry the output signal from each Hall-effect sensor. Thus in an application having three Hall-effect sensors, for example, typically at least five wires are required to generate the Hall-effect output signals and carry them to the controller—two power supply wires (Hall excitation and return) and three wires for carrying the respective outputs of the Hall-effect sensors.